Abusing annotations to add secondary-values to Python StrEnums

example.jinja2

{% for region in regions|sort %}
<label><input type="radio" name="region" value="{{ region.value }}" required> {{ region }}</label>
{% endfor %}

example.py

from typing import Annotation
from labelled_enum import LabelledEnum


class Region(LabelledEnum):
    eng: Annotated[str, "England"] = "england"
    nir: Annotated[str, "Northern Ireland"] = "northern-ireland"
    sct: Annotated[str, "Scotland"] = "scotland"
    wls: Annotated[str, "Wales"] = "wales"


jinja2_env.render("example.jinja2", {"regions": list(Region)})

labelled_enum.py

import inspect
from enum import StrEnum
from typing import Annotated, get_args


class LabelledEnum(StrEnum):
    def __str__(self) -> str:
        annotations = inspect.get_annotations(self.__class__)

        if self.name in annotations:
            args = get_args(annotations[self.name])
            if args and len(args) == 2:
                return args[1]

        return str(self.value)

test_labelled_enum.py

from typing import Annotated

from labelled_enum import LabelledEnum


def test_labelled_enum():
    class TestEnum(LabelledEnum):
        my_foo: Annotated[str, "Foo"] = "foo"
        my_bar: str = "bar"
        my_baz = "baz"

    assert TestEnum.my_foo.name == "my_foo"
    assert str(TestEnum.my_foo) == "Foo"
    assert TestEnum.my_foo.value == "foo"

    assert TestEnum.my_bar.name == "my_bar"
    assert str(TestEnum.my_bar) == "bar"
    assert TestEnum.my_bar.value == "bar"

    assert TestEnum.my_baz.name == "my_baz"
    assert str(TestEnum.my_baz) == "baz"
    assert TestEnum.my_baz.value == "baz"